Answer:
b. E (about 329 Hz)
Explanation:
Given data:
Initial length of the string l1= 24 in
initial frequency f1= 247 Hz
changed length l2= 18 in
Then we have to find the changed frequency f2= ?
We already now that
frequency f ∝ 1/length of the string l
therefore,
⇒
⇒
⇒
They will mix with air. Air consists mostly of nitrogen and oxygen but there are also traces of CO2 and noble gases in air, and helium is one of those noble gases.
The answer is A. Cones, as rods are not sensitive to color. :)
Answer:
C
Explanation:
If the theory were to be proved you you need to repeat the experiment over and over again so that way you can prove that it is true wuth the same results.
Answer:
47 mW
Explanation:
The average value of the Poynting vector, S = 0.939 W/m² = Intensity of wave, I
S = I S
Also, I = P/A where P = Et, P = power of electromagnetic wave, E = energy of electromagnetic wave in time t and t = time = 1 min = 60 s and A = area = lb since the electromagnetic waves falls on area equal to that of a rectangle.
So, S = Et/A
E = SA/t
= Slb/t
= 0.939 W/m² × 1.5 m × 2.0 m/60 s
= 2.817 W/60 s
= 0.047 W
= 47 mW
So, 47 mW of electromagnetic energy falls on the area in 1.0 minute.
